Grinding wheel assembly having multiple grinding surfaces for selective engagement with a workpiece

ABSTRACT

A grinding wheel assembly having two or more grinding surfaces which can be selectively engaged with a workpiece is described. The multiple grinding surfaces comprise separate series of spaced grinding surfaces which are alternated in their positions about the periphery of a grinding wheel assembly so that a single series of grinding surfaces can be selectively engaged with a workpiece to impart a given shape or finish to the workpiece.

United States Patent Stritzel May 13, 1975 1 GRINDING WHEEL ASSEMBLY HAVING 2,600,815 6/1952 Turner 51/209 R x MULTIPLE GRINDING SURFACES FOR 2,749,684 6/1956 Schuhmann .1 51/209 R SELECTIVE ENGAGEMENT WITH A 3,727,352 4/1973 Palazzi 51/338 WORKPIECE FOREIGN PATENTS OR APPLICATIONS [75] Inventor: Gene Smml, Webster, NY 1,098,332 l/l96l Germany 51/204 [73] Assignee: The Gleason Works, Rochester, primary E mminer ])ona1d Kelly Attorney, Agent, or FirmRa1ph E. Harper [22] Filed: Mar. 6, 1974 [57] ABSTRACT [21] Appl' 448782 A grinding wheel assembly having two or more grinding surfaces which can be selectively engaged with a [52] U.S. Cl. 51/204; 51/338 workpiece is described. The multiple grinding surfaces [51] Int. Cl B24d 7/14; B24d 7/18 comprise separate series of spaced grinding surfaces [58] Field of Search 51/204, 209 R, 206 R, 206 P, which are alternated in their positions about the pe- 51/71, 338 riphery of a grinding wheel assembly so that a single series of grinding surfaces can be selectively engaged [56] References Cited with a workpiece to impart a given shape or finish to UNITED STATES PATENTS the Workplace- 1.886,836 11/1932 Reller 51/338- 10 Claims, 2 Drawing Figures GRINDING WHEEL ASSEMBLY HAVING MULTIPLE GRINDING SURFACES FOR SELECTIVE ENGAGEMENT WITH A WORKPIECE BACKGROUND AND BRIEF DESCRIPTION OF INVENTION It has been a long time practice in the art of forming certain types of face couplings to utilize a cup-shaped grinding wheel assembly for grinding tooth slots into a face of each coupling member. Cup-shaped grinding wheels of this type, and methods for using them in the manufacture of face coupling members, are generally disclosed in U.S. Pat. Nos. 2,401 ,446; 2,405,171; 2,438,329; and 2,429,284.

The types of face coupling members which can be produced in accordance with the prior art grinding apparatus and techniques mentioned above find special application in the art of manufacturing gas turbine engines wherein separate turbine and compressor sections can be precisely assembled together with couplings of these types. In this art, it is essential that the tooth profiles of mating coupling members be precisely formed with a good surface finish to assure a correct mating of assembled components.

Recent advances in the art of manufacturing gas tut-- bine engines have emphasized the use of certain ceramic materials which are especially suitable for the high temperature environment of such engines, These materials also offer advantages in weight reduction which cannot be obtained with many conventional metals and metal alloys in certain applications. However, the use of newer, and sometimes harder, materials has made it more difficult to obtain a good surface finish with conventional grinding wheel assemblies. It has been noted, for example, that grinding wheels formed from silicon carbide or aluminum oxide materials tend to burn certain ceramic materials and to produce subsurface cracks in the materials when used for full forming of tooth slots in coupling members made from such materials. In contrast, it has been observed that socalled diamond plated grinding wheels (having steel bodies coated with a bonded layer of diamond particles) of relatively coarse grit exhibit good grinding characteristics for removing substantial quantities of ceramic material from a workpiece, but a finer grit wheel must be used to provide the type of final finish required for precision manufacture of ceramic couplings. In order to overcome these difficulties in grinding hard ceramic materials, it has become necessary to carry out two separate grinding operations, with two separate types of grinding wheels, in order to grind and finish tooth slots in ceramic couplings.

The present invention is directed to an improved grinding wheel assembly which offers the advantage of dual grinding characteristics in a single grinding wheel structure. By incorporating two separate grinding characteristics into a single assembly, it is possible to carry out rough and finish grinding of ceramic members with a single setup of the workpiece relative to a single grinding head assembly. This saves considerable time in the overall grinding operation and eliminates a problem of re-setting a workpiece relative to a new grinding wheel after an initial grinding operation has been performed. The principles of the present invention also can be applied to other types of grinding requirements where different portions of a tooth profile are formed with different grinding wheel configurations which typically require two or more grinding setups to complete. Thus, a wheel assembly may include more than two series of grinding surfaces, if desired, and the separate series of grinding surfaces can be arranged to contact and form different portions of a given tooth profile in a workpiece. In addition, separate series of grinding surfaces may be provided on other types of grinding wheel configurations.

In accordance with a specific embodiment of the present invention, a grinding wheel assembly is provided with two or more series of grinding surfaces which can be selectively engaged with a workpiece for imparting selected finish or shape characteristics to the workpiece. A preferred assembly of a grinding wheel for grinding ceramic face coupling member, includes a cup-shaped grinding wheel configuration having first and second series of spaced grinding surfaces arranged around a rim portion of the cup-shaped wheel. The first and second series of spaced grinding surfaces are alternated in their positions about the periphery of the grinding wheel, and actuating means are provided for selectively advancing and retracting one of the series of grinding surfaces relative to the other so as to present one or the other of the grinding surfaces to a workpiece. One of the series of grinding surfaces is designed for roughing out large quantities of material from a ceramic workpiece and may comprise a series of coarse grit, diamond plated segments which can be advanced and retracted relative to a main body portion of the grinding wheel assembly. The second series of grinding surfaces can comprise known silicon carbide, aluminum oxide, or fine grit diamond plated segments which can be brought into engagement with a workpiece for finishing the previously ground surfaces of the workpiece.

These and other features and advantages of the present invention will become apparent in the more detailed discussion which follows. In that discussion reference will be made to the accompanying drawings, as briefly described below.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an elevational view in cross-section of a cupshaped grinding wheel assembly manufactured in accordance with the present invention; and

FIG. 2 is-a plan view, partly in section, of a portion of the grinding wheel assembly of FIG. 1, as seen on line 2-2 of FIG. 1.

DETAILED DESCRIPTION OF INVENTION FIG. 1 illustrates a cup-shaped grinding wheel assembly designed for use in grinding tooth slots in face coupling members of the type described, for example, in US. Pat. No. 2,401,446. The cup-shaped grinding wheel assembly is illustrated in a typical mounted position on a wheel spindle 10 of a standard grinding machine designed for grinding such face coupling members.

The illustrated assembly includes a first cup-shaped member 12 having a first series of equally spaced grinding surfaces 14 formed on axially projecting rim portions thereof. A second cup-shaped member 16, or its equivalent, is fitted within the first cup-shaped member 12, and the second cup-member 16 carries a second series of grinding surfaces 18 which are arranged to be received between the positions of the first series of grinding surfaces 14. The second series of grinding surof the grinding surfaces 18 with the positions of the grinding surfaces 14. It can be seen that the two series of grinding surfaces 14 and 18 are alternated to define separate interrupted grinding surfaces about the rim portion of the cup-shaped grinding wheel assembly. These interrupted grinding surfaces have an effect of a slotted grinding wheel when engaged with a workpiece, which provides for greater flow of coolant onto the surface being finished and better cooling of the grinding site.

The second cup-shaped member 16 includes and an nular chamber means 20 for receiving an annular piston means 22 which is fitted and sealed within the annular chamber means. A conduit 24 communicates with the annular chamber means 20 to deliver hydrau lic fluid toand from the annular chamber means for advancing and retracting the annular piston means 22 therein. This provides an actuating means for advancing and retracting the second series of grinding surfaces 18 into and out of grinding positions relative to the positions of the first series of grinding surfaces 14. Thus, the second series of grinding surfaces 18 can comprise, for example, a relatively coarse grinding material which can be brought into engagement with a workpiece for roughing out tooth profiles on the workpiece while the first series of grinding surfaces 14 are out of engagement with the workpiece. After the roughing operation is completed, the second series of grinding surfaces 18 can be withdrawn to the relative position shown in FIG. 1, and the first series of grinding surfaces 14 can be brought into engagement with the same workpiece to complete and finish the grinding operation. Preferably the first cup-shaped member 12, which constitutes a major body portion of the grinding wheel assembly, carries the finishing grinding surfaces 14 so that a very rigid and precise relationship can be maintained between the finishing grinding surfaces and the workpiece.

Considering further details of the assembly shown in FIG. 1, it can be seen that the entire assembly is held in place on a terminal end portion 30 of the wheel spindle by a mounting block 32 which is retained in place by a lock nut 34. The first'cup-shaped member 12 is retained in place relative to the mounting block 32 with a spacer ring 36 and a lock nut 38 threaded to a threaded portion of the mounting block 32. The second cup-shaped member 16 is fitted within the first cup-shaped member 12 and secured thereto with screw members 40. A ring plate 42 is secured by screw members 43 to a portion of the second cup-shaped member 16 so as to partially close off the annular chamber means 20. This provides a stop limit against which the annular piston means 22 can move (downwardly, in the FIG. 1 orientation) when the annular chamber means is pressurized with hydraulic fluid. The annular piston means 22 includes a threaded surface on a depending portion 44 so as to receive an annular sleeve means 46 carrying the second series of grinding surfaces 18. A bearing sleeve 48 is provided between the sleeve means 46 and a downwardly depending portion of the second cup-shaped member 16 to reduce friction between the two members during axial movement of the sleeve member 46 relative to the cup-shaped member 16. One or more driving pins 50 can be fitted in the annular sleeve 46 for being receivedin elongate slots i of the first cup-shaped member 12 to provide a positive driving engagement between the first and second series of grinding surfaces.

The second cup-shaped member 16 can beretracted f to the withdrawn position shown in FIG. 1 by use of hy draulic pressure, if desired, but in the illustrated em- I bodiment, a number of separate spring elements 54 (see also FIG. 2) are provided between radial extended portions of the ring plate 42 and a lower surface of the annular piston means 22. The depending portion 44 of the annular piston means 22 is cut away at those loca;

tions where return springs 54 are provided. Various g sealing rings and gaskets are included in the assembly wherever needed, and a number of such devices have been omitted from the drawings for purposes of clarity.

An example of a grinding wheel assembly in accordance with the present invention would provide for a cup-shaped grinding wheel having a point diameter would be about 2 inches in length. However, this length may vary, and 10 to 15 separate grinding surfaces can be provided about the periphery of a given grinding wheel assembly. The grinding surfaces 18 would comprise a layer of relatively course diamond particles (62-120 grit) bonded tora steel body; These surfaces would then function as a roughing grinding wheel for initial shaping and finishing of a workpiece. The grind ing surfaces 14 would comprise silicon carbide or aluminum oxide materials, or they could consist of a layer of relatively fine diamond particles (600 grit. or'finer) bonded on a steel backing. These surfaces would function as a finishing grinding wheel for final shaping and I i finishing of a workpiece, and known dressing devices may be provided for the grinding surfaces 14 for coir trolling the development of the. workpiece surfaces.

Of course, other combinations or materials can be substituted for those discussed above, depending upon the material and shaping requirements for a :given workpiece. In addition, the grinding wheel assembly can be constructed and assembled from components which are somewhat different from those illustrated and discussed. For example, the grinding surfaces 18 may be carried on separate segments which are individually attached to an annular sleeve 46 or to a portion 44 of a piston assembly. Actuation ofan inner grinding.

wheel relative to an outer grinding wheel may be car-. I ried out by. fully equivalent structures to those which 7 have been described and discussed above.

What is claimed is: l. A cup-shaped grinding wheel assembly for grind-- ing tooth slots into face coupling members, comprising a first cup-shaped member having a first series of spaced grinding surfaces formed on aprojecting f rim portion therof, a second cup-shaped member having a second series of grinding surfaces arranged in positions between J the positions of said first series of grinding surfaces,

said second cup-shaped member being fitted within said first cup-shaped member for carryingsaid second series of grinding surfaces'for axial movement relative to the first cup-shaped member,

series of grinding surfaces can be brought into engagement with a workpiece while the first series of grinding surfaces are out of engagement with the workpiece. and then the first series of grinding surfaces can be brought into engagement with workpiece while the second series of grinding surfaces are out of engagement with the workpiece.

2. The assembly of claim 1 wherein said second cupshaped member includes an annular piston means which is fitted into an annular chamber means carried by said first cup-shaped member, and wherein said actuating means includes hydraulic means for moving the annular piston means within the annular chamber means.

3. The assembly of claim 2 wherein said hydraulic means functions to move said second cup-shaped member in a direction which advances said second series of grinding surfaces into a grinding position, and including spring means for returning the second cup-shaped member to a position which retracts the second series of grinding surfaces from said grinding position.

4. The assembly of claim 1 wherein said first cupshaped member includes a cup-shaped body portion having equally spaced rim portions projecting axially outwardly therefrom.

5. The assembly of claim 4 wherein said second cupshaped member includes an annular body portion having equally spaced rim portions projecting radially outwardly therefrom at a sufficient angle to be received between the spaced rim portions of said first cupshaped member so as to form a substantially continuous rim structure carrying said first and second series of grinding surfaces.

6. The assembly of claim 1 wherein said second series of grinding surfaces has a grinding characteristic for removing large quantities of materials from a workpiece to define general shapes for tooth slots in the workpiece, and wherein said first series of grinding surfaces has a grinding characteristic for imparting a final shape of finish to the tooth slots formed in the workpiece.

7. A grinding wheel assembly having multiple grinding surfaces which can be selectively engaged with a workpiece for imparting selected finish or shape characteristics to the workpiece, comprising a first series of spaced grinding surfaces for being engaged with a workpiece to form a first finish or shape in the workpiece, said first series of grinding surfaces being carried on rim structures defined by a first support member,

a second series of spaced grinding surfaces carried in alternating spaces defined between said first series of grinding surfaces for being engaged with a workpiece to form a second finish or shape in the workpiece, said second series of grinding surfaces being carried on rim structures defined by a second support member, said first and second series of grinding surfaces being arranged on a common axis of rotation in the general configuration of a cupshaped grinding wheel, and

actuating means for selectively advancing and retracting one of said series of grinding surfaces relative to the other of said series of grinding surfaces so as to present one or the other of said series of grinding surfaces to a workpiece.

8. The assembly of claim 7 wherein said second series of grinding surfaces have a grinding characteristic for removing large quantities of material from a workpiece, and wherein said first series of grinding surfaces have a grinding characteristic for imparting a final shape or finish to the workpiece.

9. The assembly of claim 1 wherein said first and second series of grinding surfaces are arranged to contact and form different portions of a given tooth profile in a workpiece.

10. The assembly of claim 7 wherein said first and second series of grinding surfaces are arranged to contact and form different portions of a given tooth profile a workpiece.

Disclaimer and Dedication 3,882,646.Gene A. Stm'teel, Webster, N.Y. GRINDING WHEEL ASSEM- BLY HAVING MULTIPLE GRINDING SURFACES FOR SE- LECTIVE ENGAGEMENT WITH A WORKPIECE. Patent dated May 13, 1975. Disclaimer and dedication filed July 20, 1977, by the assignee, The Gleason W 07"]78. Hereby disclaims and dedicates to the Public 'all claims of said patent.

[Oficial Gazette September 6, 1 977.] 

1. A cup-shaped grinding wheel assembly for grinding tooth slots into face coupling members, comprising a first cup-shaped member having a first series of spaced grinding surfaces formed on a projecting rim portion therof, a second cup-shaped member having a second series of grinding surfaces arranged in positions between the positions of said first series of grinding surfaces, said second cup-shaped member being fitted within said first cup-shaped member for carrying said second series of grinding surfaces for axial movement relative to the first cup-shaped member, actuating means for advancing and retracting said second series of grinding surfaces into and out of grinding positions relative to the positions of said first series of grinding surfaces, whereby the second series of grinding surfaces can be brought into engagement with a workpiece while the first series of grinding surfaces are out of engagement with the workpiece, and then the first series of grinding surfaces can be brought into engagement with workpiece while the second series of grinding surfaces are out of engagement with the workpiece.
 2. The assembly of claim 1 wherein said second cup-shaped member includes an annular piston means which is fitted into an annular chamber means carried by said first cup-shaped member, and wherein said actuating means includes hydraulic means for moving the annular piston means within the annular chamber means.
 3. The assembly of claim 2 wherein said hydraulic means functions to move said second cup-shaped member in a direction which advances said second series of grinding surfaces into a grinding position, and including spring means for returning the second cup-shaped member to a position which retracts the second series of grinding surfaces from said grinding position.
 4. The assembly of claim 1 wherein said first cup-shaped member includes a cup-shaped body portion having equally spaced rim portions projecting axially outwardly therefrom.
 5. The assembly of claim 4 wherein said second cup-shaped member includes an annular body portion having equally spaced rim portions projecting radially outwardly therefrom at a sufficient angle to be received between the spaced rim portions of said first cup-shaped member so as to form a substantially continuous rim structure carrying said first and second series of grinding surfaces.
 6. The assembly of claim 1 wherein said second series of grinding surfaces has a grinding characteristic for removing large quantities of materials from a workpiece to define general shapes for tooth slots in the workpiece, and wherein said first series of grinding surfaces has a grinding characteristic for imparting a final shape of finish to the tooth slots formed in the workpiece.
 7. A grinding wheel assembly having multiple grinding surfaces which can be selectively engaged with a workpiece for imparting selected finish or shape characteristics to the workpiece, comprising a first series of spaced grinding surfaces for being engaged with a workpiece to form a first finish or shape in the workpiece, said first series of grinding surfaces being carried on rim structures defined by a first support member, a second series of spaced grinding surfaces carried in alternating spaces defined between said first series of grinding surfaces for being engaged with a workpiece to form a second finish or shape in the workpiece, said second series of grinding surfaces being carried on rim structures defined by a second support member, said first and second series of grinding surfaces being arranged on a common axis of rotation in the general configuration of a cup-shaped grinding wheel, and actuating means for selectively advancing and retracting one of said series of grinding surfaces relative to the other of said series of grinding surfaces so as to present one or the other of said series of grinding surfaces to a workpiece.
 8. The assembly of claim 7 wherein said second series of grinding surfaces have a grinding characteristic for removing large quantities of material from a workpiece, and wherein said first series of grinding surfaces have a grinding characteristic for imparting a final shape or finish to the workpiece.
 9. The assembly of claim 1 wherein said first and second series of grinding surfaces are arranged to contact and form different portions of a given tooth profile in a workpiece.
 10. The assembly of claim 7 wherein said first and second series of grinding surfaces are arranged to contact and form different portions of a given tooth profile a workpiece. 